Phytochemicals from traditional medicinal plants used in the treatment of diarrhoea: modes of action and effects on intestinal function

Abstract

Medicinal plants have been used as traditional treatments for numerous human diseases for thousands of years. Diarrhoeal diseases continue to be a major cause of morbidity and mortality throughout the world and there is renewed interest in the discovery of novel compounds that can be used to fight these diseases. Numerous studies have validated the traditional use of antidiarrhoeal medicinal plants by investigating the biological activity of extracts of such plants, which have antispasmodic effects, delay intestinal transit, suppress gut motility, stimulate water adsorption or reduce electrolyte secretion. Of the numerous phytochemicals (such as alkaloids, tannins, flavonoids and terpenes) present in active extracts, tannins and flavonoids are thought to be responsible for antidiarrhoeal activity by increasing colonic water and electrolyte reabsorption. Others act by inhibiting intestinal motility. As some of the active ingredients are potentially toxic, there is a need to evaluate the safety of plant preparations. A few clinical trials have evaluated the safety and tolerability of traditional and herbal medicine preparations used to treat diarrhoea and generally indicate that minimal side effects are observed. However, with the increased popularity of plant-derived and herbal medicines in Western society, the benefits and potential dangers of these medicines must be considered.

STUDIES ON GASTROINTESTINAL EFFECTS OF <i>DESMODIUM VELUTINUM</i>: A TRADITIONAL REMEDY FOR DIARRHEA

“…Preliminary phytochemical analysis of the extract and fractions revealed the presence of typical phytoconstituents. Flavonoids, alkaloids, saponins, sterols and triterpenes have been reported to account for the antidiarrheal effects of many plants (Palombo, 2005). Flavonoids have been shown to inhibit spasmogen-induced contractions of smooth muscles (Capasso et al, 1988;Macander, 1986), intestinal secretion and small intestinal transit (Carlo et al, 1993;Viswanathan et al, 1984).…”

Antimicrobial activity of crude extracts and fractions of Vernonia polyanthes Less (assa-peixe) flowers

“…There are several reports on the use of tannins in treating various diseases in humans, including snake bites, diarrhoea, gastric ulcers and wounds (Pereira et al, 2001;Palombo, 2006). Hydrolysable tannins and derivatives have shown bacteriostatic and bactericidal activities (Kim et al, 2010).…”

Antidiarrhoeal activity of leaf methanolic extract of Rauwolfia serpentina

“…Suppression of intestinal fluid accumulation by extracts may also suggest inhibition of gastrointestinal function [13,14] . Previous studies have incriminated tannins, flavonoids, reducing sugars/glycosides among others as potent antidiarrhoeal and antidysentery agents [15] . Flavonoids have also been shown to have inhibitory actions on intestinal motility [16] .…”